BioMedical Admissions Test (BMAT) Practice Test 2026 - Free BMAT Practice Questions and Study Guide

Selective reabsorption occurs primarily in the proximal convoluted tubule (PCT) of the nephron. This structure is responsible for reabsorbing a significant majority of the essential substances filtered through the glomerulus, including glucose, amino acids, and a substantial amount of water and ions such as sodium and bicarbonate. The epithelial cells lining the PCT are adapted for this function with numerous microvilli, which increase the surface area for absorption, and a high number of mitochondria, providing the energy necessary for active transport processes.

The other parts of the nephron also participate in reabsorption but to a lesser extent. The Loop of Henle is primarily involved in the concentration of urine through countercurrent multiplication, while the distal convoluted tubule fine-tunes reabsorption later in the filtrate's journey. The glomerulus, on the other hand, is the site for initial filtration of blood, not reabsorption. Thus, the proximal convoluted tubule is the most significant location for selective reabsorption within the nephron.